Naomi Wolf thought she did too. But then the Yale-educated feminist began poring over medical research for her new book, "Vagina: A New Biography." Among the things she learned: The clitoris isn't just an external organ; it extends inside a woman's body, and many researchers believe it can be stimulated by pressure in the area popularly known as the G spot.

She also learned that in 2011 American and British researchers reported the first mapping of the distinct areas of the brain's sensory cortex that light up when different parts of a woman's sexual anatomy are stimulated — and that, when stimulated, the cervix, the rigid bottom end of the uterus, gets a brain reaction right alongside those of the clitoris and the vagina.

Yes, the cervix. Evidence is piling up that this unsung hero of female anatomy can be a key player in sexual arousal.

"If a sixth unknown sense were confirmed by science, if they found that every man had, tucked away, somewhere about his person, an extra sexual organ, for God's sake — would that not make the evening news?" Wolf writes.

There is a wide range of reasons such information isn't making its way into the mainstream media. In an interview, Wolf pointed out that many of the scientific findings are revealed in highly technical medical journals, that society remains squeamish about references to sexual anatomy and that the big drug companies that helped publicize erectile dysfunction (and medical solutions) don't have a similar financial stake in female sexual function.

But the findings do matter for the woman who's seeking to understand or improve her sexual experience, or just to know her own body, leading researchers say.

"If you don't know your body, if don't know your reaction, you are always under the control of somebody (else)" says Emmanuele Jannini, a professor of endocrinology and sexology at the University of L'Aquila in Italy.

"Knowing what is true, you are free."

We talked to Wolf and two top researchers about recent findings that haven't gotten the attention they deserve.

The cervix

The cervix's PR problems go back to the 1950s, when Alfred Kinsey's landmark book "Sexual Behaviour in the Human Female," dismissed it as "the most completely insensitive part of the female genital anatomy."

But Kinsey's own data told a different story, according to Rutgers psychology professor Barry Komisaruk, who points to a table in the Kinsey book showing that 84 percent of the women Kinsey studied could feel pressure applied to the cervix.

While Wolf emphasizes the 2011 brain activation study, which didn't distinguish between erotic sensation and, say, a feeling of pressure, the most direct evidence for the cervix's role in sexual pleasure actually comes from women's self-reports and studies in which women received cervical stimulation in laboratory settings.

"Some women clearly have orgasms from cervical stimulation," says Komisaruk, who co-authored the 2011 brain activation study. He says the role of cervical stimulation as a contributor to orgasm in some women is not controversial among sex researchers.

In 2004, Komisaruk and his colleagues completed one in a series of small but remarkable studies of sexual sensation in women with severe spinal cord injuries. The women had no external bodily sensation below the level of injury and therefore no clitoral sensation. Yet, when they applied vaginal or cervical self-stimulation in a laboratory setting, three of the women experienced orgasm. Among the implications: Vaginal and cervical stimulation alone can be sufficient for orgasm.

The 2011 brain scan study, reported in the Journal of Sexual Medicine, is important because researchers finally did for women what had been done for men in 1950: They mapped genital sensation onto specific regions of the brain's sensory cortex.

The researchers used functional magnetic resonance imaging technology and found that clitoral, vaginal and cervical self-stimulation activated distinct but overlapping regions of the brain.

"The present findings provide evidence that, rather than vaginal stimulation being just an indirect means of stimulating the clitoris, vaginal and cervical stimulation per se activate specific (brain) regions" the researchers wrote.